Digital broadcast carried out through a broadcasting satellite has been recently started. Terrestrial or ground-wave digital broadcasting has been next planned and a test for putting it into practical use has been in progress. Since those types of digital radio broadcasting provide audio programs of high quality comparable to compact discs, they are especially suitable for musical programs.
Further, audio data as well as additional program information are transmitted in the digital broadcasting. In the case of musical programs, genre information of a transmitting musical composition, its title and performers, etc., can be transmitted as such additional program information. Digital radio receivers can receive the same and indicate such genre information of a transmitted musical composition, its title and performers, etc. on a display device.
In order to make reproduced sounds much better quality, a digital radio broadcasting receiver suitable for musical programs is required to have a special effect device with audio field control functions such as an equalizer. It is further desirable to automatically control this audio field in response to genre information of a transmitting musical composition.
Conventionally, an equalizer of an audio reproduction device has been provided to control audio field characteristics in response to genre information of a musical composition played by a compact disc (see Japanese Unexamined Patent Publication No. 2001-85962, pages 3-5 and FIG. 1). The equalizer analyzes spectra of a part of a musical composition in advance to determine its frequency characteristic, judges its musical genre and automatically sets up equalizer characteristics suitable for the musical genre.
In the case of digital radio broadcasting, however, since contrary to the compact disc, a playing musical composition is transmitted on a real time basis, its frequency characteristics or the like cannot be analyzed in advance.